The invention relates to the bordering of a decorative material, or at least part of the edge of the same, by using compression and/or injection in-mold lamination with a backing material. Serving for carrying out the process is an apparatus which comprises at least two mold partsxe2x80x94forming a cavity. According to a first aspect, the invention relates to an apparatus corresponding to the precharacterizing clause of the independent claim 1. According to a second aspect, the invention relates to a process for compression or injection in-mold lamination corresponding to the precharacterizing clause of the independent claim 13 or 15, respectively.
In many areas of technology, use is made of components made of plastic which, apart from functional requirements, also have to meet esthetic demands. Automotive engineering may be mentioned as one example of many such areas, such plastic components being used here for interior trim, parcel shelves, removable interior trunk lids, dashboards and the like. To design these in an esthetically pleasing form, a decorative layer is therefore often applied to a visible side of the plastic component as a separate surface layer. For reasons of unproblematical disposal or simplified reuse, the decorative material should preferably be produced from the same material as the supporting plastic component. Such single-substance materials can be recycled much more cost-effectively than mixed materials, which first have to be separated. For producing such plastic components, the so-called compression in-mold lamination or back compression molding process was developed. This process is described in the publication xe2x80x9cKunststoffe im Automobilbauxe2x80x9d [plastics in automotive engineering], VDI-Verlag GmbH, Dusseldorf 1994. It provides that a decorative layer is fastened on an upper mold part of an opened mold, the parts of which form a cavity, in such a way that it covers the surface of the upper mold part, or the surface of the cavity, if appropriate over the full surface area. Subsequently, a molten and therefore flowable plastics compound is injected into the still opened mold, for example by means of the melt-flow method, or is placed in it by means of the layer application method. After that, the mold is closed, whereby the plastics compound is distributed uniformly in the cavity of the mold under the closing pressure, and, at least in the case of decorative materials with pores, such as for example in the case of textile materials, penetrates partly into the decorative material. A decorative material may also fuse at its surface with the backing material. The plastics compound subsequently solidifies and thereby enters into an intimate bond with the decorative layer. This compression in-mold lamination process may also be combined with the injection in-mold lamination or back injection molding process, in which the backing material is injected onto the rear side of the decorative material in the already closed mold, into which the decorative material was previously placed.
Such a compression and/or injection in-mold lamination process can be used to produce a backing layer suitable for a decorative material. The one-piece production of this backing layer, which moreover borders the edge of the decorative material, would compensate for the cutting-to-size tolerances in the decorative material and simplify production by eliminating the operation of adhesively attaching for example a carpet. However, a great problem which arises here is the positioning or secure holding of the edge of the decorative material in the cavity of a mold for compression or injection in-mold lamination. The displacement of the filled plastics material melt caused by the pressing force can, for example, cause the edge of the decorative material to be compressed or raised in an unpredictable way, so this edge may be made to shift onto the surface of the border because it is displaced by the backing material. A neatly formed border which covers the edge of the decorative material reliably and completely consequently cannot be ensured.
FR 1 496 387 and GB 2 103 534 disclose processes and apparatuses for the injection in-mold lamination of a decorative material and for the bordering of the edges of the latter. The decorative material is in each case heldxe2x80x94during a first injection phasexe2x80x94against displacement. Movable, sprung or retractable feelers, which are moved away by the pressure of the injected plastic or by the decorative material acting on them from the outside, serve as holding means. While in the case of FR 1 496 387 the decorative material is held at its corners, the holding means in GB 2 103 534 act on the surface of the decorative material.
The object of the invention is to provide an apparatus and a process for the compression and/or injection in-mold lamination of decorative materials, such as carpets, textiles or films, and for the bordering of at least part of the edge of these decorative materials with a backing material in the form of a flowable compound, with which apparatus and process the edge of this decorative material can be reliably held during the compression/injection in-mold lamination and while the bordering of the edges is being carried out, in order that this edge is completely enclosed by the border.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the apparatus for an in-mold lamination of a decorative material includes a first mold part; a pressing device forming a portion of the first mold part and being immovable with respect thereto; a second mold part defining a mold part cavity having a bottom surface; and a fixed holding device forming a portion of the second mold part and being immovable with respect thereto. The fixed holding device is raised above the bottom surface for supporting the decorative material spaced from and above the bottom surface. The pressing device faces the fixed holding device. The first mold part is movable toward the second mold part in a closing direction into a closed position for pressing the decorative material between the pressing device and the fixed holding device during in-mold lamination. In the closed position the first and second mold parts together form a closed mold cavity. The mold part cavity of the second mold part forms a portion of the closed mold cavity.
Advantages of the invention over the prior art comprise the possibility of reliably bordering even decorative materials which have a complicated or irregular spatial form.
The proposed holding means, which are fixedxe2x80x94i.e. immovable with respect to the surface of the cavity on which these holding means are arrangedxe2x80x94represent a simple device. Not only can they be produced more cost-effectively in comparison with the sprung or retractable feelers in the apparatuses of the prior art, but it can also be expected from the proposed solution that they are less susceptible to faults than the apparatuses in the prior art.
The following figures concern the schematic representation of embodiments by way of example, which show individual aspects of the apparatus according to the invention and of the process according to the invention. Any desired combinations of these aspects lead to further embodiments, which are likewise covered by the idea of the invention. These figures consequently do not in any way restrict the scope of the invention. In the figures: